The invention relates particularly to railroad auto rack cars of the type having an array of vertically positioned side panels arranged in horizontal rows and vertical columns, the rows being spaced apart vertically to provide horizontal air gaps between vertically adjacent panels. The upper and lower edge portions of each panel are in the form of a U-shaped channel having vertically disposed flanges which in the case of the lower edge of a panel is an upstanding flange and the case of the upper edge of a panel is a depending flange. The vertically adjacent panels of a column do not abut horizontally; they are spaced apart forming horizontal air gaps through which light and air enter the car. Located between each column of panels is a vertical post which supports the panels and there is a vertical air gap between the posts and the side edge portions of the panels.
While the air gaps between the panels and between the panels and posts have beneficial advantages in that they allow for admittance of light and air, it is has been found that the beneficial effects are more than outweighed by the adverse effects. Specifically, as the train moves along the track at conventional speeds, the air flowing into the interior of the car through the air gaps carries with it dust and dirt which, due to the turbulence and swirling action of the air, tends to damage the paint finishes and vinyl tops of the brand new automobiles which are being transported. This of course is not desirable.